Session: Are There Secular and Developmental Changes in the Relationship Between Risk and Protective Factors and Marijuana Use? (Society for Prevention Research 24th Annual Meeting)

The issue of potential increases in substance use in the context of state-level liberalization of marijuana policies has been on the forefront of public health debates in recent years. In order to design effective prevention and intervention services for substance misuse, we have to understand the relationship between malleable risk and protective factors (RPFs) and substance use. It is possible that the new legal context has changed the relationship between RPFs and marijuana use, with some factors increasing their importance and other factors becoming less salient. Furthermore, it is likely that certain RPFs are more prominent in predicting substance use during some but not other developmental periods. The three studies included in this symposium examine the developmental and secular trends in the relationship between RPFs and marijuana use. The findings highlight salient targets, and their timing, for prevention and intervention programs aimed at reducing the prevalence and frequency of adolescent marijuana use.

Study 1 used eight waves of state-representative survey data from Washington State to examine the issue of potential decoupling between perceived harm of marijuana use and adolescent marijuana use that has been found in national and other survey data in recent years. The results indicate that spillover effects from decreases in alcohol and cigarette use counteracted the influence of increased marijuana risk factors and explain much of the observed decoupling in trends for marijuana use and perceived harm.

Study 2 used data from the longitudinal panel of the Community Youth Development Study to zoom in on the developmental interplay between marijuana-specific risk factors such as parental, peer and individual norms and attitudes about marijuana and marijuana use over the course of adolescence. The results provide evidence of reciprocal predictive associations between marijuana use in mid-adolescence and both parental attitudes about marijuana use and peer marijuana use.

Study 3 used data from the youngest cohort of the Pittsburgh Youth Study to examine whether childhood and adolescent RPFs that have differentiated marijuana users from non-users can predict subsequent desistance from adolescent heavy marijuana use. The results indicate that the examined RPFs predict adolescent use but do not prospectively differentiate heavy users who desist from those who continue to use heavily in young adulthood, highlighting developmental changes in salience of RPFs over time.

The discussant, who is a Federal employee, will discuss the importance of these findings for public health and prevention efforts.